In organic chemistry, a glycosyl group is a univalent free radical or substituent structure obtained by removing the hydroxyl (−OH) group from the hemiacetal (−CH(OH)O−) group found in the cyclic form of a monosaccharide and, by extension, of a lower oligosaccharide. Glycosyl also reacts with inorganic acids, such as phosphoric acid, forming an ester such as glucose 1-phosphate.^[1]

Examples

In cellulose, glycosyl groups link together 1,4-β-D-glucosyl units to form chains of (1,4-β-D-glucosyl)_n. Other examples include ribityl in 6,7-Dimethyl-8-ribityllumazine, and glycosylamines.

Alternative substituent groups

Instead of the hemiacetal hydroxyl group, a hydrogen atom can be removed to form a substituent, for example the hydrogen from the C3 hydroxyl of a glucose molecule. Then the substituent is called D-glucopyranos-3-O-yl as it appears in the name of the drug Mifamurtide.

Recent detection of the Au³⁺ in living organism was possible through the use of C-glycosyl pyrene, where its permeability through cell membrane and fluorescence properties were used to detect Au³⁺.^[2]